This is a perennial which grows as a clump, found on grassy banks and pastures.
The leaves are an elongated oval with two lobes at the base which point downwards and distinguish them from Sheep's Sorrel. In June and July the reddish-green flowers are borne on whorled spikes up to 60 cm high. The male and female parts are on separate plants (dioecious), and are wind-pollinated.
Common Sorrel has long had medicinal and culinary uses, the oxalic acid content gives the leaves a mildly sour flavour and they can be added to salads or cooked like spinach. It is grown as a cut-and-come-again crop, providing greens from spring to autumn; the flowering stems are removed to put the energy into leaf production. If the leaves are boiled to a pulp it can be used as a stewed rhubarb substitute to serve with crème fraîche, yoghurt or ice cream. French Sorrel (Rumex scutatus) has smaller triangular leaves with a more concentrated flavour.
The leaves are similar in shape to Lords-and-ladies so care is needed if picking but the latter is usually in shady areas and Sorrel in the open.

Medicinally it is used as a spring tonic to 'cleanse' the blood, and has astringent properties if used externally.

Common Sorrel is not usually a problem weed, it remains as a single clump and is easily removed.
A systemic or translocated weedkiller such as Glyphosate will kill the whole plant. In the lawn a selective weedkiller can be used as a spot weeder.

See also Sheep's Sorrel

Nicholas Culpepper
(17th century astrologer-physician)
"Of great use against the scurvy if eaten in spring as salad."